Vector and Bitmap Graphics
Vector Graphics are infinitely scalable, which means no matter how large they are printed they will always look crisp. As a general rule vector elements should be used wherever possible for items such as logos, text, illustrations, graphical elements, shapes and lines. Bitmap Graphics are made up of pixels. Common bitmap file types are .jpg, .bmp, .tiff, .png and .gif. When a bitmap image is scaled larger than its native dimensions it will become pixelated (blocky) when printed. Bitmap images should primarily be used for such elements as photographs, 3D renders and some textural elements. When using bitmap elements in your artwork, try to use the highest resolution possible (300dpi or higher is preferred). Bitmap images downloaded from the internet are often low resolution and heavily compressed meaning they aren't always ideal for printing. If you enlarge the internet image to the size needed in the print, then view it at 100% you will be able to see if the resolution is good enough for printing.